Listerine mouthwash may prevent gonorrhoea from spreading, new research suggests.
The mouthwash, which is readily available from supermarkets and pharmacies, has been found to curb the growth of the bacteria responsible for gonorrhoea.
Daily rinsing and gargling with the product might be a cheap and easy way of helping to control the spread of the infection, the researchers said.
They added that new cases of gonorrhoea among men are on the rise in many countries amid declining condom use, with the bulk of cases among gay and bisexual men.
According to the study, rising rates of gonorrhoea heighten the risk of the emergence of antibiotic resistant strains of Neisseria gonnorhoeae (N gonorrhoeae), the bacteria responsible for the infection.
Because of this, the need for a preventive measure that doesn’t rely on condoms is even more urgent.
As far back as 1879 and before the creation of antibiotics, the manufacturer of Listerine claimed that it could be used to cure gonorrhoea, but no published research previously tested this claim.
In a bid to rectify this, the researchers assessed whether Listerine could curb the growth of N gonorrhoeae in laboratory tests and in sexually active gay and bisexual men in a clinical trial.
For the laboratory tests, different dilutions of Listerine Cool Mint and Total Care, both of which contain 21.6% alcohol, were applied to N gonorrhoeae to see which of any of them might curb growth of the bacteria.
By way of a comparison, a salt water (saline) solution was similarly applied to an identical set of bacteria.
When applied for one minute, the researchers found Listerine dilutions “significantly” reduced the number of N gonorrhoeae bacteria, whereas the saline solution did not.
The clinical trial involved 196 gay and bisexual men who had previously tested positive for gonorrhoea in their mouths and/or throat, and who were returning for treatment at one sexual health clinic in Melbourne, Australia, between May 2015 and February 2016.
Almost a third (58) tested positive for the bacteria in their throat on the return visit.
Thirty three of these men were randomly assigned to rinse and gargle with Listerine and 25 to rinse and gargle with the saline solution.
After rinsing and gargling for one minute, the proportion of viable gonorrhoea in the throat was 52% among the men using Listerine compared with 84% among those using saline.
The men using Listerine were also 80% less likely to test positive for gonorrhoea in their throat five minutes after gargling than were the men using the saline solution.
The researchers admitted that the monitoring period was short, so the possibility that the effects of the mouthwash might be short-lived can’t be ruled out. But the laboratory test results would suggest otherwise, they said.
A larger trial is currently under way to confirm these results and see whether the use of mouthwash could curb the spread of gonorrhoea.
The researchers said: “If daily use of mouthwash was shown to reduce the duration of untreated infection and/or reduce the probability of acquisition of N gonorrhoeae, then this readily available, condom-less, and low cost intervention may have very significant public health implications in the control of gonorrhoea.”
The research is published online in the journal Sexually Transmitted Infections.